The present invention generally relates to improvement in apparatus and method for separation of liquid from a liquid-vapor mixture and, more particularly, is directed to an improved liquid-vapor separation device and method which utilizes both gravitational and centrifugal forces to provide improved efficiency in the separation of entrained liquid from a liquid-vapor mixture. In this regard, an important aspect of the present invention is concerned with the utilization of this improved liquid-vapor separation device and method in place of a conventional vapor head in an evaporation apparatus.
The operation of evaporation or concentration of liquid solutions through solvent removal is achieved with various forms of evaporator apparatus such as, for example, calandria type evaporators and long tube vertical evaporators, all of which conventionally utilize gravity for separation of liquid droplets from a vapor stream discharged from the heater component thereof. In order to achieve effective separation of entrained liquid from the vapors emitted from the heater via such gravitational separation devices, it is essential that the vapor velocity be substantially reduced upon being discharged from the heater. Heretofore this velocity reduction has been achieved by the use of an enlarged entrainment disengaging space, or vapor head. Such vapor heads, in order to achieve the desired degree of liquid removal from the liquid-vapor mixture, are inherently large in size and as a result thereof characterized by high material and labor costs. Another disadvantage of such vapor heads is that they typically require field fabrication, as opposed to shop fabrication.
In accordance with the present invention, an improved liquid-vapor separation and method are provided which are capable of achieving upwards of 99% removal of liquid from a liquid-vapor mixture such as, for example, that which is discharged from the tube side of a heater in a natural circulation evaporator. If desired, however, this device and method can be used alone or in conjunction with auxiliary liquid-vapor separation equipment such as a tangential separator or the like. The device is substantially smaller in size than a conventional vapor head and offers significant advantages insofar as reduced capital cost, not only by reason of lower material and labor costs, but also because of its being able to be shop-fabricated and shipped to the construction site rather than requiring field fabrication.
This apparatus, in accordance with an important aspect of this invention, includes a generally horizontally-disposed arcuate passageway which interconnects the outlet of the tube side of the heater component of the evaporator to a condensor or subsequent effect heater. A floor plate is disposed in the arcuate passageway in spaced-away relation from the side walls thereof so as to permit drainage of liquid collected on the interior walls of the passageway into a liquid-collecting section which is provided with a suitable drain for removal of the thus-collected liquid. The floor plate, however, is of sufficient size to minimize re-entrainment of the collected liquid. Adjacent the outlet end of the device, a Borda-type device can be provided which incorporates anti-swirl baffles extending from the outer walls thereof to the interior of the passageway to eliminate turbulence in the vapor.
It is, therefore, an object of the present invention to provide an improved apparatus and method for removal of entrained liquid particles from a liquid-vapor mixture.
Another object of the present invention is to provide an improved evaporator apparatus and method wherein separation of entrained liquid from a liquid-vapor mixture exiting from the heater tubes is achieved through the utilization of both gravitational and centrifugal forces.
Another object of the present invention is to provide an improved evaporator apparatus and method wherein separation of entrained liquid from a liquid-vapor mixture exiting from the heater tubes thereof is achieved through the utilization of a liquid-vapor separation device which is substantially smaller in size, less costly to produce than a conventional vapor head and which also offers the advantage of being able to be shop fabricated.
Another object of the present invention is to provide an improved liquid-vapor separation device which provides improved performance over conventional liquid-vapor separation devices such as, for example, enlarged entrainment disengaging spaces or vapor heads.
Another object of the present invention is to provide an improved liquid-separation apparatus and method which are particularly suitable for use in natural circulation evaporators.
Another object of the present invention is to provide an improved liquid-vapor separation apparatus and method which can be used either by itself or in combination with auxiliary liquid-vapor separation equipment.